Software Defined Networking

Like server virtualization before it, software-defined-networking (SDN) is gaining tremendous traction in the data center, due to its ability to reduce the complexity, expense, and time associated with network administration. And in light of the exponential growth of traffic stemming from increasing virtualization, real-time applications, and the adoption of cloud-based services, SDN has arrived just in time.

The major difference between SDN and traditional networking lies in its model of controller-based networking. SDN essentially separates control plane functionality from switches across the data center into a single centralized software entity, leaving only the data plane functions in the individual switches.

With this separation, network devices become simpler and easier to manage, as a centralized controller has a complete end-to-end view of the entire network, and knowledge of all network paths and device capabilities resides in a single application. The centralized controller provides the visibility and control necessary to move application workloads between compute resources connected to different physical switches without requiring network reconfigurations.

Three approaches to SDN

At this point in time, there are three basic approaches for implementing software defined networking. The OpenFlow standard is a secure communications protocol that enables remote programming of data plane functions in switches. Many switch vendors have implemented support for OpenFlow within their data plane architectures.

The second SDN approach is being driven by Software and Virtualization specialists like VMware and Microsoft offer a hypervisor-based network virtualization model called Network Virtualization Overlay (NVO). Like server virtualization, NVO introduces virtual switches that allow an organization to run multiple virtual networks on a single physical network, with each virtual network appearing to run as a physical network.

The third approach leverages a programmable framework where individual switches retain their control plane functions. An Application Programming Interface (API) allows control of the switches local data plane functions.

All of these represent valid approaches to SDN.

The benefits of SDN

Regardless of which approach you decide to take, SDN offers a number of key advantages that are common to all:

• Centralized provisioning – SDN provides a centralized view of the entire network, simplifying management and provisioning. Because SDN supports management of both physical and virtual switches and network devices from a central controller, IT managers can experiment with network configuration without impacting the network.
• Better security – In virtualized environments, network management is a challenge. When virtual machines move in and out of physical networks, it’s difficult to consistently apply firewall and content filtering polices. The SDN Controller provides a central point of control to distribute security and policy information consistently throughout the enterprise.
• Reduced operating costs – Because routine deployments, network administration, and troubleshooting can be centralized and automated, SDN can reduce operating costs over a long period of time.
• Reduced capital expenditures – SDN makes it easier to extend the useful life of compatible existing commoditized hardware, which can be repurposed using instructions from the SDN controller.
• Enhanced content delivery – SDN gives administrators the ability to shape and control data traffic dynamically. This makes it easier to improve the quality of service for VOIP, streaming and other bandwidth-intensive traffic.

While it’s clear that SDN can deliver significant advantages in virtually any environment, there are a number of issues specific to your infrastructure that must be considered before moving forward.

To help you evaluate the approach that will yield the greatest efficiency for your organization, a Zones account executive can arrange a conversation with a certified solution architect from the Zones Advanced Solutions Group.

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